WO2012093887A2

WO2012093887A2 - Method and apparatus for measuring system signal

Info

Publication number: WO2012093887A2
Application number: PCT/KR2012/000148
Authority: WO
Inventors: 정정수; 김성훈; 정경인; 김상범
Original assignee: 삼성전자 주식회사
Priority date: 2011-01-07
Filing date: 2012-01-06
Publication date: 2012-07-12
Also published as: US9338746B2; EP2663119A4; EP2663119A2; US20140016492A1; WO2012093887A3; EP2663119B1; KR20120080403A

Abstract

The present invention relates to a method and apparatus for measuring a signal. According to one embodiment of the present invention, a signal measuring method may comprise the steps of: determining whether or not a current subframe corresponds to a measurement period; measuring a serving cell signal when the current subframe corresponds to the measurement period; determining whether a current measurement mode is a normal scan mode or a short scan mode in which a serving cell signal is more frequently measured than in the normal scan mode; determining whether or not the measured serving cell signal is less than a preset low signal threshold value when the current measurement mode is the normal scan mode; and changing the current measurement mode to the short scan mode when the measured serving cell signal is less than the low signal threshold value. According to one embodiment of the present invention, a system signal measuring method and apparatus which can quickly reflect the surrounding environment while efficiently using power is provided.

Description

System signal measuring method and apparatus

The present invention relates to a system signal measuring method and apparatus.

The mobile communication system targeted by the present invention includes a first generation of analog type, a second generation of digital type, and a fourth generation mobile communication system that provides ultra-high speed multimedia service following the third generation of high speed multimedia service of IMT-2000. It may include.

Representative mobile communication systems having a channel structure for high-speed data transmission among the third generation mobile communication systems include a CDMA High Rate Packet Data (HRPD) system or a WCDMA High Speed Packet Access (HSPA). The CDMA HRPD system is a system using a code division multiple access (CDMA) scheme.

1 is a structural diagram of a conventional HRPD system.

The HRPD system includes a packet data service node (hereinafter referred to as a PDSN) 101 for transmitting high-speed packet data to the base station 103 in connection with the Internet network, and a packet controller for controlling the base station 103 ( Packet Control Function (PCF) 102. The base station 103 wirelessly communicates with a plurality of terminals 104 and transmits the high speed packet data to a terminal having the best transmission rate.

The 4th generation mobile communication system developed from the 3rd generation mobile communication system such as the HRPD system is aiming at a transmission speed of 20Mbps or more for high speed multimedia service. The fourth generation mobile communication system mainly uses orthogonal frequencies, such as orthogonal frequency division multiplexing (OFDM). A representative example of such a 4G mobile communication system is an LTE or LTE-Advanced (LTE-A) system which is being standardized in 3GPP.

2 is a structural diagram of a conventional LTE system.

LTE system wirelessly communicates with a plurality of terminals 201, MME and serving gateway (S-GW) for managing the mobility, call processing and data transmission paths of the base station 202 and the terminal providing a high-speed multimedia service 203 and a PDN-GW (PDN-GW, P-GW) 204 connected to the Internet network and transmitting high-speed packet data to the terminal through the base station.

In recent years, due to the continuous development of communication technology, devices such as various controllers, measuring instruments, and home appliances, which have not been connected to a communication system, are being connected to wired and wireless communication systems. These devices connected to the communication system can perform operations such as reading the scale of the device or controlling the device by hand through the communication system without human intervention, thereby improving efficiency and reducing maintenance costs. .

Unlike traditional communication in which a person is a subject, communication between a controller, a measuring instrument, a home appliance, and a communication system is called machine-to-machine communication (M2M communication). In the early 1990s, when the concept of M2M communication was first introduced, remote control or telematics was considered an example of M2M communication, and the market itself was very limited. However, in the last few years, M2M communication has been growing at a rapid pace, increasing the number of target devices and growing into a market that is drawing attention not only in Korea but also in the world. In particular, intelligent metering that measures flow management, remote monitoring of machinery and equipment, operating hours on construction machinery and automatic measurement of heat or electricity usage in point-of-sales and security-related applications. M2M communication has a great influence in the fields of (Smart Meter).

The communication terminal between the device and the device has various features different from the terminal in the conventional sense. Some of these features are listed below.

1. Devices such as controllers and instruments are not mobile or exhibit mobility at very low frequency.

2. In the case of some terminal-to-device communication terminal, the communication is performed in the form of sending and receiving data only at a preset time.

3. Some device-to-device communication terminals should be able to accommodate the delay even when data communication is performed. (Delay tolerant)

4. For some device-to-device communication terminals, functions related to voice communication are unnecessary.

5. If paging is not required from the mobile communication system and data communication is required, the terminal may request connection establishment.

6. As various types of devices support device-to-device communication, there may be a greater number of terminals in a densely populated area than in the conventional sense.

7. In the case of communication terminals between devices operating using batteries, it may be difficult to replace batteries one by one. That is, the inter-device communication terminal should be designed to use power efficiently.

Among the above-described characteristics of the device-to-device communication terminal, a terminal that does not need paging does not need to frequently observe a message transmitted by the base station to receive paging. In the case of the terminals, in order to receive system information transmitted by the system, an intended operation may be performed only by occasionally receiving a control channel. Reducing the frequency of receiving control channels is also a very important technique to ensure high power efficiency.

In order to introduce such an operation into the LTE system, a method of increasing the period in which the UE observes the system in the idle state has been proposed. The period in which the UE observes the system in the idle state is called a DRX (Discontinuous Reception) period.

3 illustrates a DRX cycle of a communication terminal between a conventional terminal and a device.

The horizontal axis 301 of FIG. 3 means a system frame number which is a transmission period of LTE. The conventional terminal may be designed to have a relatively short DRX cycle 302, while the inter-device communication terminal has a longer DRX cycle 303.

In the LTE system, a period for observing a radio channel is defined to be linked with a DRX period. That is, the terminal performs an operation of measuring the reception sensitivity of the radio channel by a given number within the DRX cycle. Accordingly, as shown in FIG. 3, when the DRX cycle is longer, a conventional channel change monitoring cycle is lengthened, and thus a terminal in a wireless environment does not quickly reflect the change. That is, even when the channel situation is worsened and a plurality of radio channel measurement results are combined to determine reselection to another base station, it may take a long time to make a decision about the radio channel measurement cycle. This can cause problems such as not receiving paging for several DRX cycles.

The present invention has been proposed to solve the above problems, and an object thereof is to provide a method and apparatus for measuring a system signal which can efficiently reflect the surrounding environment while using power efficiently.

In order to achieve the above object, a signal measuring method according to an embodiment of the present invention, determining whether the current subframe corresponds to the measurement period, if the current subframe is the measurement period, measuring the serving cell signal, the current Determining whether the measurement mode is a normal scan mode or a short scan mode that measures a serving cell signal more frequently than the normal scan mode; and if the current measurement mode is a normal scan mode, whether the measured serving cell signal is below a preset lower limit signal threshold And determining the current measurement mode to a short scan mode when the measured serving cell signal is less than the lower limit signal threshold.

In order to achieve the above object, the terminal according to an embodiment of the present invention, the control unit for determining whether the current subframe corresponds to the measurement period and includes a radio frequency unit for measuring the serving cell signal if the current subframe is a measurement period. Can be. The controller determines whether the current measurement mode is a normal scan mode or a short scan mode in which a serving cell signal is measured more frequently than the normal scan mode, and when the current measurement mode is a normal scan mode, the measured serving cell signal is a preset lower limit signal threshold. If the measured serving cell signal is less than the lower limit signal threshold, the current measurement mode may be changed to a short scan mode.

According to an embodiment of the present invention, it is possible to provide a method and apparatus for measuring a system signal that can quickly reflect a surrounding environment while using power efficiently.

In addition, according to an embodiment of the present invention, the device-to-device communication terminal can prevent the situation of missing call setup or SMS message by selecting the best base station faster when the channel situation is bad.

1 is a structural diagram of a conventional HRPD system.

2 is a structural diagram of a conventional LTE system.

4 illustrates a signal measuring method according to an embodiment of the present invention.

5 is a flowchart illustrating a signal measurement process of the device-to-device communication terminal according to the first embodiment of the present invention.

6 is a flowchart illustrating a signal measurement process of the device-to-device communication terminal according to the second embodiment of the present invention.

7 is a block diagram of the terminal 730 and the base station 700 according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. Like reference numerals refer to the same elements as shown in the drawings, even though they may be shown on different drawings, and in the following description, detailed descriptions of related well-known functions or constructions are unnecessary. If it is determined that it can be blurred, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

As described above, in order to more efficiently support the characteristics of the device-to-device communication terminal, a method of increasing the Discontinuous Reception (DRX) period, which is a period of observing the system in the idle state, has been proposed. In the LTE system, a period for observing a radio channel is defined to be linked with a DRX period. That is, the terminal performs an operation of measuring the reception sensitivity of the wireless channel by a given number within the DRX cycle. Therefore, when the DRX cycle is lengthened, a cycle for observing a change in a conventional channel is lengthened, which may cause a problem that the change in the wireless environment cannot be quickly reflected.

The present invention proposes a method of quickly reflecting a channel situation by changing a period for measuring the surrounding signal according to the surrounding channel situation in which the device-to-device communication terminal including the serving base station to solve the problem.

4 is a diagram illustrating a DRX cycle setting process according to an embodiment of the present invention. In step 401, the device-to-device communication terminal measures the peripheral signal once every DRX cycle. Hereinafter, in this specification, a state in which the peripheral signal is measured a predetermined number of times per DRX cycle is referred to as a "normal scan mode".

Thereafter, in step 402, the inter-device communication terminal detects that the strength of the signal received from the serving base station is smaller than the preset lower limit signal threshold. In this case, the inter-device communication terminal measures the peripheral signal more frequently by reducing the period for measuring the peripheral signal to a value promised between the base station and the terminal (a value smaller than the original period). Hereinafter, the state in which the peripheral signal is measured more frequently in this specification is referred to as a "short scan mode".

The inter-device communication terminal then detects that the strength of the signal received from the serving base station in step 403 exceeds a preset upper limit signal threshold. In this case, the device-to-device communication terminal restores the period of measuring the peripheral signal to its original state. In addition, even when the inter-device communication terminal changes the communication target to a new base station, it may return to the original signal measurement period (normal scan mode) in step 403.

In this specification, a method of changing the DRX cycle according to a channel situation is proposed as a method of changing the signal measurement cycle. At this time, the number of times of measuring the peripheral signal within the DRX cycle can be kept the same. In addition, the present invention proposes a method of changing only the number of measurements of the peripheral signal within the DRX cycle while maintaining the DRX cycle as a method of changing the signal measurement cycle.

5 is a flowchart illustrating a signal measurement process of the device-to-device communication terminal according to the first embodiment of the present invention. The operation in subframe k of the inter-device communication terminal is described.

Referring to FIG. 5, in step 501, the inter-device communication terminal determines whether the corresponding terminal is operating in the DRX mode. If the terminal does not operate in the DRX mode performs the operation defined in the conventional LTE. Since the operation of the conventional LTE is a known technique, a detailed description thereof will be omitted. If the terminal is operating in the DRX mode, the process proceeds to step 502.

In step 502, the inter-device communication terminal determines whether the subframe k corresponds to a period for measuring the peripheral signal. If the subframe k does not correspond to the period for measuring the peripheral signal, the terminal performs the operation defined in the conventional LTE. If subframe k corresponds to a period for measuring a signal of a neighboring base station in DRX mode, the process proceeds to step 503.

In operation 503, the device-to-device communication terminal performs a signal measurement operation on a neighboring base station. Thereafter, in step 504, the terminal performs a filtering operation in which the past measured values of the surrounding signals are reflected to the newly measured value at a specific ratio. The terminal uses the filtered value in step 504 as a measurement for the neighbor base station in a later step. The filtering operation of step 504 may be omitted. Thereafter, in step 505, the UE determines whether the UE is currently operating in a short scan mode in which peripheral signals are received at short intervals. If not, the process proceeds to step 506.

In step 506, the terminal determines whether the signal measurement value of the serving base station currently being observed for call reception is smaller than a predetermined lower limit signal threshold value threshold_a between the base station and the terminal. If the signal measurement of the serving base station is smaller than the lower limit signal threshold, the process proceeds to step 507. The terminal initializes previous measurement values stored in step 507. In step 508, the terminal sets the DRX cycle to a new value promised between the base station and the terminal. The DRX cycle set in step 508 may be set to a smaller value than the cycle when operating in the normal scan mode. In addition, in step 508, the terminal sets the period for measuring the peripheral signal to the short scan mode (Short scan mode). Operation after step 508 follows that of conventional LTE. In addition, if the signal measurement value of the serving base station is greater than the preset lower limit signal threshold in step 506, the subsequent operation follows the operation of the conventional LTE.

If the UE is operating in a short scan mode (“Short scan mode”) in step 505, the process proceeds to step 509. In step 509, the terminal determines whether the signal measurement value of the serving base station is greater than a predetermined upper limit signal threshold value threshold_b. If the signal measurement of the serving base station is greater than the upper limit signal threshold, the process proceeds to step 510.

In step 510, the terminal resets the DRX cycle to the cycle used in the conventional normal scan mode and sets the method of measuring the peripheral signal to the normal scan mode. Operation after step 510 follows the operation of the conventional LTE system.

If the signal measurement value of the serving base station is smaller than the upper limit signal threshold in step 509, the process proceeds to step 511. In step 511, the terminal performs an operation related to changing a serving base station. Since the detailed operation of step 511 is not suggested by the present invention, the detailed description is omitted here. In step 512, the terminal determines whether a new serving base station is selected as a result of step 511. If a new serving base station is selected, the process proceeds to step 510. As described above, the UE resets the DRX cycle to the cycle used in the conventional normal scan mode and sets the method of measuring the peripheral signal to the normal scan mode in step 510. If a new serving base station is not selected in step 512, the terminal performs subsequent operations according to the scheme defined in the conventional LTE.

6 is a flowchart illustrating a signal measurement process of the device-to-device communication terminal according to the second embodiment of the present invention. The operation in subframe k of the inter-device communication terminal is described.

Referring to FIG. 6, in step 601, the inter-device communication terminal determines whether the corresponding terminal is operating in the DRX mode. If the terminal does not operate in the DRX mode performs the operation defined in the conventional LTE. Since the operation of the conventional LTE is a known technique, a detailed description thereof will be omitted. If the terminal is operating in the DRX mode, the process proceeds to step 602.

In step 602, the inter-device communication terminal determines whether the subframe k corresponds to a period for measuring the peripheral signal. If the subframe k does not correspond to the period for measuring the peripheral signal, the terminal performs the operation defined in the conventional LTE. If subframe k corresponds to a period for measuring a signal of a neighboring base station in DRX mode, the process proceeds to step 603.

In operation 603, the device-to-device communication terminal performs a signal measurement operation on a neighbor base station. Thereafter, in step 604, the terminal performs a filtering operation in which the past measured values of the neighboring signals are reflected at a new ratio. The terminal uses the filtered value in step 604 as a measurement for the neighboring base station in a later step. The filtering operation of step 604 may be omitted. Thereafter, in step 605, the UE determines whether the UE is currently operating in a short scan mode in which peripheral signals are received at short intervals. If it is not the short scan mode, the process proceeds to step 606.

In step 606, the terminal determines whether the signal measurement value of the serving base station currently observed for call reception is smaller than a predetermined lower limit signal threshold value threshold_a between the base station and the terminal. If the signal measurement value of the serving base station is smaller than the lower limit signal threshold, the process proceeds to step 607. The terminal initializes previous measurement values stored in step 607.

In step 608, the terminal sets settings related to signal measurement to a value independent of the DRX cycle promised between the base station and the terminal. That is, in step 608, the UE may set the number of times of measuring the ambient signal within the DRX cycle to a value greater than a predetermined number of times. In addition, the time for determining the strength of the signal by measuring the ambient signal may be set to a value shorter or longer than a predetermined time. You can also change the way you filter and the previously measured signal so that the new measured value is more reflected in the final measured value. In addition, in step 608, the terminal sets a period for measuring the peripheral signal to the short scan mode ("Short scan mode"). Operation after step 608 follows that of conventional LTE. In addition, if the signal measurement value of the serving base station is greater than the lower limit signal threshold in step 606, the subsequent operation follows the operation of the conventional LTE.

If the UE is operating in a short scan mode (“Short scan mode”) in step 605, the process proceeds to step 609. In step 609, the UE determines whether the signal measurement value of the serving base station is greater than a predetermined upper limit signal threshold value threshold_b. If the signal measurement of the serving base station is greater than the upper limit signal threshold, the process proceeds to step 610.

In step 610, the UE resets the settings related to signal measurement to the values used in the conventional normal scan mode and sets the method of measuring the peripheral signals to the normal scan mode. Operation after step 610 follows the operation of the conventional LTE system.

If the signal measurement value of the serving base station in step 609 is smaller than the upper limit signal threshold, the process proceeds to step 611. In step 611, the terminal performs an operation related to changing a serving base station. Detailed operation of step 611 is not suggested by the present invention, and thus detailed description thereof is omitted here. In step 612, the terminal determines whether a new serving base station is selected as a result of step 611. If a new serving base station is selected, the process proceeds to step 610. As described above, the UE resets the DRX cycle to the cycle used in the conventional normal scan mode in step 610 and sets the method of measuring the peripheral signal to the normal scan mode. If a new serving base station is not selected in step 612, the terminal performs subsequent operations according to the scheme defined in the conventional LTE.

The base station 700 according to an embodiment of the present invention includes a scheduler and controller 710, an RF unit 720, and a data queue 715. A terminal according to an embodiment of the present invention includes a transmitter 735, a demodulator 740, a decoder 750, a controller 760, an encoder 755. And a modulator 745.

The control unit 710 of the base station 700 may set various parameter values for controlling signal measurement periods for peripheral signals, such as various threshold values, setting values, and DRX cycles, used in any one of the embodiments of the present invention. The controller 710 may set the parameter value when the call is set up or terminated by the terminal 730, when the terminal 730 and the base station 700 negotiate setting values related to a wireless connection, or the base station 700 coverage. All of the terminals 730 in the broadcast may be transmitted in the form of. The data queue 715 of the base station 700 classifies the data received from the upper network node according to the terminal 730 or the service and stores the data in the queue. The scheduler and the controller 710 selectively control data of a specific user or a specific queue in consideration of forward channel condition information, service characteristics, fairness, etc., in which the terminals 730 transmit data stored in each queue. The radio frequency unit 720 transmits the screened control data signal or control signal to the terminal 730.

The controller 760 of the terminal 730 increases or decreases the period for measuring the peripheral signal according to the channel condition of the neighboring base station including the serving base station according to any one of the embodiments of the present invention. In addition, the controller 760 performs an operation of resetting the period for measuring the peripheral signal to an initial value when a situation of selecting a new serving base station occurs. The terminal detects the signal received by the transceiver 735 at every measurement period determined by the controller 760. The terminal 730 demodulates the detected signal in the demodulator 740, decodes the signal in the decoder 750, and determines and processes the signal in the controller 760. The encoder 755 encodes the data to be transmitted and the modulator 745 modulates the encoded data.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the appended claims, but also by the equivalents of the claims.

Claims

Determining whether the current subframe corresponds to a measurement period;

Measuring a serving cell signal if the current subframe is a measurement period;

Determining whether the current measurement mode is a normal scan mode or a short scan mode in which the serving cell signal is measured more frequently than the normal scan mode;

Determining whether the measured serving cell signal is less than a preset lower limit signal threshold value when a current measurement mode is a normal scan mode; And

Changing the current measurement mode to a short scan mode if the measured serving cell signal is less than the lower limit signal threshold.
The method of claim 1,

And resetting a previous measurement result if the current measurement mode is a normal scan mode and the measured serving cell signal is less than the lower limit signal threshold.
The method of claim 2,

Changing a serving cell signal measurement parameter to a DRX independent parameter if the current measurement mode is a normal scan mode and the measured serving cell signal is below the lower limit signal threshold.
The method of claim 1,

If the current measurement mode is the short scan mode, determining whether the measured serving cell signal exceeds a preset upper limit signal threshold; And

Changing the current measurement mode to a normal scan mode if the measured serving cell signal exceeds a preset upper limit signal threshold.
The method of claim 4, wherein

Attempting cell reselection if the current measurement mode is the short scan mode and the measured serving cell signal does not exceed a preset upper limit signal threshold; And

Changing the current measurement mode to the normal scan mode when the cell is reselected as a result of the attempt of cell reselection.
The method of claim 4, wherein

Changing a serving cell signal measurement parameter to a DRX independent parameter if a current measurement mode is the short scan mode and the measured serving cell signal exceeds a preset upper limit signal threshold.
The method of claim 5,

Changing the serving cell signal measurement parameter to a DRX independent parameter if the cell is reselected as a result of the attempt of cell reselection.
A controller which determines whether a current subframe corresponds to a measurement period; And

If the current subframe is a measurement period includes a transceiver for measuring the serving cell signal,

The controller determines whether the current measurement mode is a normal scan mode or a short scan mode in which a serving cell signal is measured more frequently than the normal scan mode, and when the current measurement mode is a normal scan mode, the measured serving cell signal is a preset lower limit signal threshold. Determining whether it is less than a value, and if the measured serving cell signal is less than the lower limit signal threshold, changing the current measurement mode to a short scan mode.
The method of claim 8,

The control unit resets a previous measurement result when the current measurement mode is a normal scan mode and the measured serving cell signal is less than the lower limit signal threshold.
The method of claim 9,

And the control unit changes the serving cell signal measurement parameter to a DRX independent parameter when the current measurement mode is a normal scan mode and the measured serving cell signal is less than the lower limit signal threshold.
The method of claim 8,

The controller determines whether the measured serving cell signal exceeds a preset upper limit signal threshold when the current measurement mode is the short scan mode, and measures the current when the measured serving cell signal exceeds a preset upper limit signal threshold. Terminal for changing the mode to the normal scan mode.
The method of claim 11,

If the current measurement mode is the short scan mode and the measured serving cell signal does not exceed a preset upper limit signal threshold, the controller attempts to reselect the cell, and if the cell is reselected as a result of the cell reselection attempt, Terminal for changing the measurement mode to the normal scan mode.
The method of claim 11,

And the control unit changes the serving cell signal measurement parameter to a DRX independent parameter when the current measurement mode is the short scan mode and the measured serving cell signal exceeds a preset upper limit signal threshold.
The method of claim 12,

And the control unit changes the serving cell signal measurement parameter to a DRX independent parameter when the cell is reselected as a result of the cell reselection attempt.